CN104279456A - Illumination system for optical detection, detection system using illumination system and detection method - Google Patents

Abstract

This case discloses a lighting system for optical detection and a detection system and detection method using the lighting system. Through the first illumination light projected forwardly to the detection area and the two second illumination light projected diagonally to the detection area , and two third illumination rays with the largest incident angle relative to the detection area to illuminate the detection area together. The third illumination light includes a wavelength segment shorter than the first illumination light and the second illumination light, and then passes through the color linear The scanning camera outputs optical image data of different spectra for defect detection, and the obtained mixed image is segmented into each spectral color frequency to distinguish oxidation and dust on the circuit board. The third illumination light can further enhance the The ability to identify defects in optical images, thereby reducing the probability of misjudgment by the inspection system during inspection.

Description

Illumination system for optical inspection, inspection system and inspection method using same

technical field

The invention relates to a related technology of optical detection, in particular to an illumination system for optical detection, a detection system and a detection method using the illumination system.

Background technique

The light source system plays a pivotal role in automatic optical inspection (AOI). For example, in the manufacturing process of liquid crystal display, semiconductor integrated circuit chips and related circuits, precise automatic optical inspection is required.

The detection of wire defects on the circuit substrate is a link in automatic optical inspection. The traditional detection method is to make the detection light irradiate the object to be tested in the forward direction. Since the wires are generally made of metal materials (such as copper materials), they have High reflective ability, judge whether there is any defect such as breakage or disconnection of the wire by whether there is reflected light of the irradiated light in the forward direction.

However, this method often has dust or other attachments on the metal wires, because the attachments will scatter the forward incident light, so that the metal wires under the attachments cannot reflect the normal incident light. It is reflected back, which in turn causes a misjudgment that the wire with the attachment is defective, and also causes processing costs in subsequent further inspections.

Contents of the invention

The main purpose of the present invention is to quickly obtain the defect status of the object under test through the special configuration of the lighting system.

Another object of the present invention is to reduce the misjudgment of the detection system.

Another object of the present invention is to enable the detection system to provide image data that can quickly identify oxidized areas and dust in the optical image.

In order to achieve the above purpose and other purposes, the present invention proposes an illumination system for optical detection, the system provides illumination light to a detection area, including: a first light source group, which is generated from above the detection area and projected to the detection area the first illuminating light of the area; the second light source group is used to generate two second illuminating light, the two second illuminating light are respectively generated from above the detection area and obliquely projected to the detection area; and the third The light source group is used to generate two third illumination rays, which are respectively generated from above the detection area and obliquely projected to the detection area, wherein the third illumination light is incident on the detection area The incident angle is greater than the incident angle of the second illuminating light, and the third illuminating light includes a wavelength band shorter than that of the first illuminating light and the second illuminating light.

In order to achieve the above and other objectives, the present invention further proposes an optical detection system, which includes the above-mentioned lighting system and an image capture device, the image capture device is arranged above the detection area to capture the light of the lighting system. The reflected light rays projected by the first to third light source groups onto the detection area are used for optical detection of the detection area.

In order to achieve the above purpose and other purposes, the present invention further proposes an optical detection method, which uses the above optical detection system to perform optical detection of the object to be measured in the detection area, including the following steps: making the first to third The first to third irradiation rays of the light source group are projected onto the object to be tested in the detection area; the color scanning camera generates the captured image data including the first wavelength band and the second wavelength band wavelength; the first The second judging step is to judge whether there is a dark part representing a defect according to the image data of the first wavelength band. When the judgment result is "No", the detection result of the detection area is normal, and when the judgment result is "Yes", enter the second step. The second judgment step; that is, the second judgment step is carried out, and it is judged according to the image data of the second wavelength band whether the dark part determined as a defect in the first wavelength band is still a dark part in the image data of the first wavelength band. When the determination result is "Yes", the detection result that the dark portion is defective is generated, and when the determination result is "No", the detection result that the dark portion determined in the first determination step is not defective is generated.

In an embodiment of the present invention, the image data of the first wavelength band is the image data of the red wavelength band, and the image data of the second wavelength band is the image data of the blue wavelength band.

In an embodiment of the present invention, the third illuminating light is illuminating light with only blue wavelength band.

In an embodiment of the present invention, the optical paths of the two illuminating rays of the second light source group are symmetrical to each other with respect to the center of the detection area, and the optical paths of the two illuminating rays of the third light source group are relative to the center of the detection area. The centers of the detection areas are also symmetrical to each other.

In an embodiment of the present invention, the first to third light source groups generate corresponding illumination light through LED linear light sources or optical fiber linear light sources.

Therefore, the present invention provides a high-speed color line scan camera. This camera is used to analyze the illumination light of different angles and the light of different wavelength bands. It can not only be used to distinguish oxidation and dust on the circuit board or defects on other substrates. , which can reduce the probability of misjudgment of the system during inspection.

Description of drawings

Fig. 1 is a system diagram of a detection system in an embodiment of the present invention.

Fig. 2 is a detailed system diagram of the detection system in an embodiment of the present invention.

Fig. 3 is a flowchart of an optical detection method in an embodiment of the present invention.

Figure 4a is the image capture data of copper wire disconnection in the red wavelength range.

Figure 4b is the image capture data of copper wire disconnection in the blue light wavelength band.

Figure 5a is the image capture data of the copper wire with dust in the red wavelength range.

Figure 5b is the image capture data of the copper wire with dust in the blue light wavelength band.

Figure 6a is the image capture data of copper wire with oxidized area under the red wavelength band.

Figure 6b is the image capture data of copper wire with oxidized area under blue light wavelength range.

【Symbol Description】

100 first light source group

102 First light source

104 The second optical assembly of the first light source group

106 first optical assembly

110 first lighting rays

200 second light source group

202 Second light source

204 The second optical assembly of the second light source group

210 second lighting rays

300 third light source group

302 The third light source

304 The second optical assembly of the third light source group

308 blue light wavelength filter components

310 third lighting rays

500 detection area

600 image capture devices

701 Background material

702 defect

703 copper wire area

801 background material

802 dust particles

803 copper wire area

804 copper area

901 background material

902 oxidation area

903 copper area

S10～S42 steps

Detailed ways

In order to fully understand the purpose, features and effects of the present invention, now through the following specific embodiments, and cooperate with the accompanying drawings, the present invention is described in detail, as follows:

The present invention uses three groups of light sources arranged at different irradiation angles to irradiate an object under test (such as a circuit substrate) and the use of reflected light in different wavelength bands to detect defects and enhance optical The identification of oxidized areas and dust in the image reduces the probability of misjudgment of the imaging system.

First please refer to FIG. 1 , which is a schematic diagram of a detection system in an embodiment of the present invention. The illumination system for optical detection in this embodiment of the present invention is used to provide illumination light to a detection area 500 , and the illumination system includes: a first light source group 100 , a second light source group 200 and a third light source group 300 . The illumination system illuminates the detection area 500, so that the optical detection system including the illumination system and the image capture device 600 can project through the image capture device 600 through the first to third light source groups 100-300 of the illumination system. After reaching the detection area 500 , the reflected light is picked up, so that the detection area 500 can be optically detected.

The first light source group 100 is used to generate the first illuminating light 110 that is forwardly projected onto the detecting area 500 from above the detecting area 500, and the first illuminating light 110 may only have the first wavelength band or include There is light in the first wavelength band (for example, white light).

The second light source group 200 is used to generate two second illumination rays 210 , and the second illumination rays 210 are obliquely projected to the detection region 500 from above the detection region 500 . Wherein, the second illuminating light 210 may be a light having only the first wavelength band or a light including the first wavelength band (eg, white light). Wherein, the first wavelength band of the illumination light of the first light source group 100 and the second light source group 200 is preferably a red wavelength band.

The third light source group 300 is used to generate two third illumination rays 310 , and the third illumination rays 310 project obliquely from above the detection region 500 to the detection region 500 . Wherein, the incident angle of the third illuminating light 310 incident on the detection area 500 is greater than the incident angle of the second illuminating light 210 , and the third illuminating light 310 includes a wavelength shorter than that of the first illuminating light 110 and the second illuminating light The wavelength band of the light 210 . Wherein, the preferred third illuminating light 310 is the illuminating light with only the blue wavelength band, and the preferred incident angle of the third illuminating light 310 incident on the detection area 500 is 60 degrees to 80 degrees, referring to The incident angle is the angle between the illumination light 310 and the normal on the detection area 500 .

As shown in FIG. 1 , the incident angle of the third illumination light 310 of the third light source group 300 incident on the detection area 500 is larger than the incident angle of the second illumination light 210 of the second light source group 200 . The incident angle referred to is the angle between the illumination light and the normal on the detection area 500 . In addition, regarding the arrangement of the second light source group 200 and the third light source group 300 relative to the detection area 500, the two preferred light source groups 200, 300 are symmetrical to the normal on the detection area 500 and presents a symmetrical configuration. Taking the detection area 500 as a reference point, the configuration position of the first light source group 100 shown in FIG. 1 is higher than that of the second light source group 200 and the third light source group 300. This is just an example and not a limitation. Any light source group that can incident obliquely to the detection area 500 can be used as the second light source group 200 or the third light source group 300 .

Please refer to FIG. 2 , which is a detailed system diagram of the detection system in an embodiment of the present invention. FIG. 2 is described with a detailed configuration framework, and those skilled in the art should understand that it is an example rather than a limitation, and any other configuration device or system that can meet the light conditions described in the present invention is acceptable. Do not deviate from the technical scope of the present invention.

As shown in FIG. 2 , the first light source group 100 may include: a first light source 102 , a first optical component 106 and a second optical component 104 . As mentioned above, the first light source 102 can provide illumination light including the red wavelength band or only the red wavelength band. For example, the first light source 102 can be directly a red light generator, or a white light The generator is additionally matched with a filter component to achieve the provision of illumination light with the red wavelength band.

The second light source group 200 and the third light source group 300 described later in the present invention will also use the same second optical assembly 104, which are defined by the same term in the following description, but different in the figure Component symbols to distinguish. The first optical component 106 of the first light source group 100 is disposed above the detection area 500 for guiding the light output from the first light source 102 to the detection area 500 to become the first illumination light 110 projected forward. The second optical component 104 is disposed at the light output end of the first light source 102 for converging the output light of the first light source 102 onto the detection area 500 . Wherein, the first optical component 106 can be, for example, a semi-reflective and semi-transmissive optical component or other optical components that can achieve the same function; Optical components, two Fresnel lens groups connected by discontinuous curved surfaces, or other optical components that can achieve the same function.

As shown in FIG. 2 , the second light source group 200 may include: two second light sources 202 and two second optical components 204 . The second light source 202 can be a white light generator as mentioned above. The second optical component 204 is disposed at the light output end of the second light source 202 for focusing the output light of the second light source 202 onto the detection area 500 . In addition, the second light source group 200 can also use a filter assembly to make the outgoing light only have the wavelength band of red light (not shown in the figure).

As shown in FIG. 2 , the third light source group 300 may include: two third light sources 302 , two third optical components 304 and two blue light wavelength filter components 308 . The third light source 302 can be a white light generator as mentioned above. The second optical assembly 304 is disposed at the light output end of each of the third light sources 302 for converging the output light of the third light sources 302 onto the detection area 500 . The blue light wavelength band filter component 308 is configured under a preferred implementation mode. In actual implementation, as long as the wavelength contained in the third illuminating light 310 has a wavelength band shorter than that of the first illuminating light 110 and the second illuminating light 210 wavelength, the configuration of the lighting system of the present invention can be completed; and even, a light source that directly outputs the blue wavelength band is used as the third light source 302, so that the blue wavelength band filter assembly 308 does not need to be added. The second optical component 304 is disposed at the light output end of the third light source 302 for focusing the output light of the third light source 302 onto the detection area 500 . In a preferred embodiment, two blue light wavelength filter components 308 are arranged between the corresponding third light source 302 and the second optical component 304, so as to filter the output light of the third light source 302 to have only blue light wavelength segment of the third illumination ray 310 .

Next, please refer to FIG. 3 , which is a flowchart of an optical detection method in an embodiment of the present invention, so as to perform optical detection of an object to be detected located in the detection area.

First, step S10: irradiating the first to third light source groups to the detection area with the irradiating light rays, so that the first to third irradiating light rays from the first to the third light source groups are projected onto the object under test in the detection area .

Next, step S20: capture of image data, the color scanning camera generates the captured image data including the wavelengths of the first wavelength band and the second wavelength band.

Next, Step S30: Carry out the first judgment step, which judges whether there is a dark portion representing a defect according to the image data of the first wavelength band, and when the image data of the first wavelength band does not have a dark portion representing a defect (that is, judge When the result is "no", the detection result of the normal detection of the detection area is generated, and the judgment of entering step S32 is no defect, and when the image data of the first wavelength band has a dark part representing the defect (that is, the judgment result is "yes") ”) enter step S40.

Next, step S40: Carry out a second determination step, which is to determine whether the dark part determined as a defect in the first determination step S30 in the image data of the first wavelength band is still Dark part, when it is still a dark part (that is, when the determination result is "yes"), it produces the detection result (step S42) that is a defect at the dark part, and when it is not a dark part but a bright part (that is, the determination result is "No ") produces the detection result that the dark part determined in the first determination step has no defect, and the determination of entering step S32 is no defect.

In one embodiment, in an optical detection system including an illumination system and an image capture device 600, the image capture device 600 is a color scanning camera (for example, a linear color camera), and an image captured by the color scanning camera The image data includes the image data of the red wavelength segment, the green wavelength segment and the blue wavelength segment, and then the image data captured by the color scanning camera is the red wavelength segment, the green wavelength segment and the blue wavelength segment The image data of the first wavelength band is the image data of the red wavelength band, and the image data of the second wavelength band is the image data of the blue wavelength band.

Then, the first wavelength segment and image data are respectively the image data of the red wavelength segment and the red wavelength segment, and the second wavelength segment and image data are respectively the image data of the blue wavelength segment and the blue wavelength segment Take a practical example as an example. Wherein, the image capture device 600 adopts a high-speed color line scan camera.

Next, please refer to FIG. 4a and FIG. 4b at the same time. FIG. 4a is the image capture data of the disconnected copper wire under the red wavelength range; FIG. 4b is the image capture data of the copper wire disconnection under the blue wavelength range. First of all, the first judgment step, Figure 4a shows the image data of R Chanel after the mixed image is obtained by the color line scan camera and then segmented from the mixed image. In FIG. 4 a , it can be seen that the copper line area 703 is a bright area, while the background material 701 is a dark area. The defect 702 is located just above the copper line area 703, and becomes a dark area at this time. Generally, the detection system will think that the defect 702 is not illuminated, which means that the copper wire in this area is disconnected, so the light that does not reflect after the light reaches this area enters the color line scan camera. However, the second judgment step is performed again, and Fig. 4b shows the image data of B Chanel after the mixed image is obtained by the color line scan camera and then divided into the mixed image. In FIG. 4 b , it can be seen that the copper line area 703 is still a bright area, while the background material 701 is still a dark area. The defect 702 just sits on the copper wire area 703, and it also becomes a dark area at this time, and it can be confirmed that it is a true copper wire disconnection, and it is determined to be a true defect. Accordingly, in the second determination step, the identification accuracy of the detection system of the present invention can be improved due to the assistance of the illumination light having only the second waveband.

Next, please refer to FIG. 5a and FIG. 5b at the same time. FIG. 5a is the image capture data of the copper wire with dust in the red wavelength range; FIG. 5b is the image capture data of the copper wire with dust in the blue wavelength range. Figure 5a shows the image data of R Chanel after the mixed image is obtained by the color line scan camera and then the mixed image is segmented. In FIG. 5 a , it can be seen that the copper line area 803 and the copper surface area 804 are bright areas, while the background material 801 is a dark area. The dust particle 802 is just above the copper wire area 803, and its brightness is a darker area compared with the height of the copper wire area. It is impossible to distinguish whether it is a false defect or not just by looking at the image of RChanel. Therefore, the second determination step is performed again, and FIG. 5 b shows the image data of the BChanel after the mixed image is obtained by the color line scan camera and then divided into the mixed image. In FIG. 5 b , it can be seen that the copper line area 803 and the copper surface area 804 are bright areas, while the background material 801 is a dark area. Dust particles 802 just above the copper wire area 803 are bright areas. This is because the mixed light source structure of the present invention passes through a blue filter assembly at a low angle (with a larger incident angle), and the dust can be brightened by the blue light at this low angle (the wavelength of the blue light is shorter, and the scattering situation more significant), thus resulting in a strong contrast with R Chanel. Accordingly, through the comparison of the two image data of R Chanel and B Chanel, it can be known that this is a false defect (dust). Therefore, due to the assistance of the illumination light with only the second waveband in the second determination step, the phenomenon that the dust particles scatter the incident light can improve the identification accuracy of the detection system of the present invention.

Next, please refer to Fig. 6a and Fig. 6b at the same time. Fig. 6a is the image capture data of the copper wire with oxidized area under the red wavelength band; Fig. 6b is the image capture data of the copper wire with oxidized area under the blue light wavelength band data. Figure 6a is the mixed image obtained by the color line scan camera, and then the mixed image is segmented into the image data of R Chanel. In FIG. 6a it can be seen that the copper surface area 903 is a bright area, while the background material 901 is a dark area. When the oxidized area 902 is on the copper surface area 903, it is a gray area at this time. If you just judge by looking at R Chanel, you will think this area is a defect. Therefore, the second judgment step is carried out again. Figure 6b is the image data of B Chanel after the mixed image obtained by the color line scan camera is divided into the mixed image. In FIG. 6b it can be seen that the copper surface area 903 is a bright area, while the background material 901 is a dark area. When the oxidized area 902 is on the copper surface area 903, because it is close to the brightness of the copper surface area 903, it can be known that this is a false defect (oxidation) through the comparison of the two image data of R Chanel and B Chanel. The non-copper area 903 actually has disconnection.

The second optical assembly 104, 204, 304 of the present invention, for example, can adopt an optical assembly with a discontinuous light-concentrating surface, two Fresnel lens groups that are joined by discontinuous curved surfaces, or other methods that can achieve the same functional optical components.

To sum up, the present invention uses a high-speed color line scan camera, which is matched with the analysis of illumination light at different angles and light at different wavelengths, not only to distinguish oxidation and dust on the circuit board or defects on other substrates, but also to It can reduce the probability of misjudgment of the system during inspection.

The present invention has been disclosed above with preferred embodiments, but those skilled in the art should understand that the embodiments are only used to describe the present invention, and should not be construed as limiting the scope of the present invention. It should be noted that all changes and substitutions equivalent to this embodiment should be included within the scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims (12)

1. A lighting system for optical detection, providing lighting light to a detection area, comprising: a first light source group, which generates a first illumination light forwardly projected onto the detection area from above the detection area; The second light source group is used to generate two second illumination rays, and the two second illumination rays are respectively generated from above the detection area and obliquely projected to the detection area; and The third light source group is used to generate two third illumination rays, and the two third illumination rays are respectively generated obliquely from above the detection area and projected to the detection area, It is characterized in that the incident angle of the third illuminating light incident on the detection area is greater than the incident angle of the second illuminating light, and the third illuminating light includes a wavelength band shorter than that of the first illuminating light and the second illuminating light . 2. The lighting system according to claim 1, characterized in that, the third lighting light is lighting light having only blue wavelength band. 3. The lighting system according to claim 2, wherein the optical paths of the two illumination rays of the second light source group are symmetrical to each other with respect to the center of the detection area, and the two illumination rays of the third light source group The light paths are also symmetrical with respect to the center of the detection zone. 4 . The illumination system according to claim 2 , wherein an incident angle of the third illumination light incident on the detection area is 60° to 80°. 5. The lighting system as claimed in claim 3, wherein the first and second lighting lights are lighting lights with only red wavelength band. 6 . The lighting system according to claim 3 , wherein the first to third light source groups generate corresponding lighting rays through LED linear light sources or optical fiber linear light sources. 7. The lighting system according to claim 3, wherein the first light source group comprises: first light source; a first optical component configured above the detection area to guide the output light of the first light source to the detection area; and a second optical component configured at the light output end of the first light source to converge the output light of the first light source to the detection area; The second light source group includes: two second light sources; and Two second optical components are respectively arranged at the light output end of the second light source, so as to converge the output light of each second light source to the detection area; and The third light source group includes: two third light sources; Two third optical components are respectively arranged at the light output end of the third light source, so as to converge the output light of each third light source to the detection area; and Two blue light wavelength band filter components are arranged between the third light source and the third optical component, so as to filter the output light of the third light source into only the illumination light with the blue light wavelength band. 8. The lighting system according to claim 3, wherein the first light source group comprises: first light source; a first optical component configured above the detection area to guide the output light of the first light source to the detection area; and a second optical component configured at the light output end of the first light source to converge the output light of the first light source to the detection area; The second light source group includes: two second light sources; and Two second optical components are respectively arranged at the light output end of the second light source, so as to converge the output light of the second light source to the detection area; and The third light source group includes: two third light sources; and Two third optical components are respectively arranged at the light output end of the third light source, so as to converge the output light of the third light to the detection area; Wherein the output light of the two third light sources is the illumination light only having the blue wavelength band. 9. An optical detection system, comprising an image capture device and the illumination system according to any one of claims 1-8, characterized in that the image capture device is arranged above the detection area to capture the The first to third light source groups of the illumination system project the reflected light rays onto the detection area for optical detection of the detection area. 10. The optical inspection system according to claim 9, wherein the image capture device is a color scanning camera, and a piece of image data captured by the color scanning camera includes red wavelength bands, green wavelength bands and image data in the blue-ray wavelength range. 11. An optical detection method, which is to use the optical detection system according to claim 9 to perform optical detection in which the object to be tested is located in the detection area, it is characterized in that it comprises the following steps: projecting the first to third irradiation light rays of the first to third light source groups onto the object under test in the detection area; The color scanning camera generates captured image data including wavelengths of the first wavelength band and the second wavelength band; Carrying out the first judgment step, judging whether there is a dark part representing a defect according to the image data of the first wavelength band, when the judgment result is "No", the detection result of the detection area is normal, and when the judgment result is "Yes" enter the second judgment step; and Carrying out the second judgment step, judging according to the image data of the second wavelength band whether the dark part determined as a defect in the first wavelength band image data is still a dark part, when the judgment result is "yes" The detection result that the dark portion is a defect is generated, and the detection result that the dark portion determined in the first determination step has no defect is generated when the determination result is “No”. 12 . The optical inspection method according to claim 11 , wherein the image data in the first wavelength range is image data in the red wavelength range, and the image data in the second wavelength range is image data in the blue wavelength range. 13 .